Over the past 3 years, the Research Project 4 (RP4) Investigators have assembled a cohort of asthmatics and studied their respiratory responses to Florida red tide by comparing exposure and nonexposure periods. We have demonstrated statistically significant changes in inflammatory markers, respiratory function and reported symptoms in asthmatics with only 1 hour of acute beach exposure;no significant changes were observed during similar non-exposure periods. Parallel to these studies, the Investigators have assisted the Centers for Disease Control and Prevention (CDC) and the Florida Dept of Health (FDOH) in assembling and evaluating an occupational cohort. This represents the first time that possible health effects from exposure to aerosolized Florida red tide toxins have been evaluated epidemiologically in human populations. Over the next 5 years, working with the Toxin Probes and Assays Core, the Field Logistics and Development Core, and Project by Cheng, we propose to continue studying the exposures and health effects for humans due to aerosol exposures to Florida Red Tide, using new measures of exposure and physiologic effects. Specifically, we will annually collect pre- and post-exposure health effects and environmental exposure data at a time when a Florida red tide occurs and at a time with no Florida red tide for 1 hour of beach exposure. In addition, the investigators will annually conduct a 5 day Follow-up Study directly following the 1 hour Acute Exposure Study to collect data on persistent and delayed health effects from the acute exposure, as well as from possible repetitive exposures to Florida red tides toxins over 5 days. Additional data will be collected every 6 months to evaluate the severity and controllability of the asthmatics in the prior 6 months. The data from these annual studies (exposed and unexposed) will be evaluated longitudinally to explore possible chronic effects of varying Florida red tide toxin levels on the health of asthmatics, as well as subpopulations among the asthmatics. Based on the results of the animals models ( Projects by Benson and Abraham) and our epidemiologic work, we will use the following measurable physiologic effects: reported symptoms and measures of asthma controllability, spirometry, nasal swabs for inflammatory mediators, and exhaled condensates for acidification and selected cytokines, as well as the exposure measures of environmental and personal monitoring and nasal swabs for brevetoxins. The possible association between the uncontrollability of asthma associated with Florida red tide toxin exposure over time will be evaluated. In addition, the possible dose response relationship will be explored between long term exposure to Florida red tide toxins and their effects on measurable physiologic effects in asthmatics by evaluating coastal vs inland residents. Over the proposed 5 years, the project investigators will also take advantage of advancements in the science made by the other Projects to refine methods for measuring human exposures and physiologic effects from this environmental occurrence. The data from these studies will provide valuable medical and public health information concerning acute, subacute and chronic respiratory effects of aerosolized red tide toxin exposures annually in asthmatics over a 5 year period.